[Subcutaneous localizations of Castleman's pseudolymphoma. Review of the literature apropos of a case].

The angiofollicular lymphoid hyperplasia, first described in 1954 by Castleman in the mediastinum, is a quite rare pseudolymphoma where there are few subcutaneous localizations. Since 1954, more than 300 observations were published including mediastino-pulmonary forms (about 60 p. 100 of the cases) intra-abdominal forms (15 p. 100 of the cases) and superficial forms which represent 25 p. 100 of the cases and associate superficial ganglionic, intra-muscular and subcutaneous localizations. The authors report the observation of a 44-year-old negro who had a subcutaneous tumefaction of the left elbow which appeared recently without a functional sign nor a biological change. The histological findings allowed the diagnosis of Castleman's pseudolymphoma in a hyalino-vascular form or Flendrig's type II. The evolution was marked a few weeks later by a local recurrence of which a second surgery has secured the recovery. The detailed study of the 76 cases of Castleman's superficial pseudo-tumours published in the literature allows us to recall the features of this disease which affects especially the young adult without prevalence of sex at about 25 years old. The circumstances of discovery are univocal, isolated palpable subcutaneous tumefaction in most of the cases. The localizations are distributed by decreasing incidence as following: latero-cervical, axillary, sus-clavicular, inguinal, vulvar, abdominal wall, shoulder, arm, forearm with a few bifocal forms. The histological aspect associated a predominant lymphoid population and vessels with fibro-hyalinous wall which morphological variations have permitted to individualize three forms: a plasmocytic form or Flendrig's type I which should be a stage of beginning often associated with hematological changes, a hyalino-vascular form or Flendrig's type II more frequent and a mixed form or intermediary type. The immunofluorescence, histo-enzymology and immunohistochemistry studies reveal a changeable polyclonal plasmocytosis and a predominance of T-suppressors in the lymphocytic population. The histological differential diagnosis of the superficial forms of the Castleman's pseudolymphoma is rarely set with certain lymphoma in case of ganglionic localization. On the other hand isolated subcutaneous localizations must be distinguished of the Kimura's disease and of the angiolymphoid hyperplasia with eosinophils where the vessels have a different morphology. The evolution is favorable in most of the cases and surgical exeresis insures the recovery.(ABSTRACT TRUNCATED AT 400 WORDS)